Automatic fastening machines, i.e., machines that automatically insert fasteners into a part for assembly purposes, are used in a variety of industrial environments. In the aircraft industry fastening machines that automatically drill a hole and install a fastener (e.g., a rivet) are used in fabricating wings and other parts of an aircraft. Typically, such fastening machines are fed by fastener feed systems that include a feeder tube through which fasteners are moved by gravitational or other forces (e.g., air pressure) to the machine. Either headed or non-headed fasteners are installed by the fastening machines depending upon the particular structural requirements of the fabricated part. The present invention was developed for use primarily with headed fasteners.
Most modern fastening machines designed to install headed fasteners require the headed fasteners to be delivered in a particular orientation, usually shank first. Since the cross-sectional area of the feeder tubes of such machines are sized so that the headed fastener cannot be inverted once a fastener enters the tube, orientation checking mechanisms are located at some point along the feeder tube. The checking mechanisms detect the orientation of a headed fastener passing the feeder tube and reject (i.e., remove from the feeder tube) any headed fasteners that are improperly oriented.
The cost of handling rejected fasteners would be greatly reduced if the fasteners could be consistently fed to the feeder tube in the correct orientation. To this end, the present invention is directed to a device for conveying headed fasteners from a supply source (in which the fasteners are stored in random orientation) to the feeder tube of a fastening machine in a manner that results in each headed fastener entering the feeder tube in the proper orientation.